Newton's laws of motion

📋 Teacher notes

• •An object stays at rest or moves at constant velocity unless a net external force acts on it.
• •Inertia is the resistance to change in motion — heavier objects have more inertia.
• •On a frictionless surface (μ=0), a moving block never stops. On Earth, friction provides the net force.
• •Common misconception: students think a moving object needs a continuous force to keep moving. It doesn't — only to accelerate it.
• •Demonstrate: set initial velocity, then toggle friction on/off mid-animation to show inertia.